A recent glowing tendency in the global environment protection has urged the industry to develop efficient compressors consuming less fossil fuel.
FIG. 58 shows a sectional view of a conventional electrical enclosed refrigerant-compressor. FIG. 59 illustrates a supporting structure for the compressor. Closed container (hereinafter referred to simply as “container”) 1 pools oil 2 at the bottom, and accommodates motor section 5 having stator 3 and rotor 4, as well as compressor section 6 driven by motor section 5. Compressor unit 7 having motor section 5 and compressor section 6 is resiliently supported by compression spring (hereinafter referred to simply as “spring”) 8 in container 1.
Crankshaft 9 has main shaft 9A, to which rotor 4 is fixed, and eccentric section 9B formed eccentrically with respect to main shaft 9A. Lubricating pump 10 is prepared to crankshaft 9. Main shaft 9A is supported by bearing 23. Cylinder block 11 has compressing room 13 including typically cylindrical bore 12. Piston 14 goes back and forth in bore 12, and is coupled to eccentric section 9B with a sliding mechanism. An end face of bore 12 is sealed by valve plate 15.
Head 16 forms a high-pressure room. Discharging path 17, which guides compressed refrigerant gas from head 16 to outside container 1, is coupled via pipe 18 to a high pressure side (not shown) of a refrigerating cycle disposed outside container 1. Pipe 18 is made of polymer material of heat resistance, refrigerant resistance, and oil resistance. Pipe 18 prevents discharging path 17 from resonating.
Holder 20 made of synthetic resin is mounted to a head of each one of bolts 19 which fasten the stator of motor section 5. Another holder 22 made of synthetic resin is mounted to each one of projections 21 provided on the inner wall of container 1. Springs 8 are placed surrounding holders 20 and 22.
An operation of the foregoing refrigerant compressor is demonstrated hereinafter. Commercial power is supplied to motor section 5 and rotates rotor 4, which spins crankshaft 9, so that eccentric section 9B eccentrically moves to drive piston 14. The reciprocation of piston 14 in bore 12 puts refrigerant gas guided into container 1 into compressor room 13 via a suction valve (not shown). The refrigerant gas is then continuously compressed, and transferred outside container 1 via a discharging valve (not shown), discharging path 17, and pipe 18.
The rotation of crankshaft 9 prompts lubricating pump 10 to supply oil 2 to respective sliding sections for lubricating the sliding sections, and oil 2 is discharged from a tip of eccentric section 9B into container 1. Oil 2 also works as seal between piston 14 and bore 12.
Main shaft 9A of crankshaft 9 and bearing 23 form a sliding section with each other as well as piston 14 and bore 12. In the conventional compressor, a first member of the sliding section is made of nitrided iron-based material undergone manganese phosphate process, and a second member thereof is made of aluminum die-cast undergone anodizing. Those techniques are disclosed in, e.g. Japanese Patent Application Non-Examined Publication No. H06-117371.
However, if the sliding sections are processed by manganese phosphate which has a low hardness, the manganese-phosphate layer tends to wear away when metallic contact occurs on the sliding section at the operation start because oil film does not yet cover the sliding section. Then the friction coefficient becomes higher, and sliding loss possibly increases. A smaller clearance between the sliding sections for decreasing the friction coefficient will produce metallic contact, which wears the manganese-phosphate layer away, so that friction increases or abnormal friction possibly occurs. Further, between piston 14 and bore 12, piston 14 wears much, so that the space in between becomes greater. As a result, compressed refrigerant gas may leak from the space between piston 14 and bore 12, thereby lowering the efficiency.
On top of that, use of the oil of low viscosity for lowering the viscous resistance will reveal the foregoing problems more expressly.
Another prior art discloses a compressor of which sliding sections are applied with molybdenum disulfide (MoS2), as solid lubricant on their surfaces. Such a compressor is disclosed, e.g. Japanese Patent Application Non-Examined Publication Nos. H08-121361 and H09-112469.
MoS2 includes a binder of polyamide-imidic resin (PAI) because it is applied to the sliding sections; however, PAI has a higher friction coefficient than MoS2, so that the sliding loss increases. In the case of using metal such as iron or aluminum as base material of the sliding sections, those metals have binding force to the PAI (binder) weaker than those of ordinal metallic bonds. At the sliding section on which MoS2 is applied, peeling occurs on the interface between the base material and the binder. As a result, MoS2 cannot exert its advantage of increasing abrasion resistance, and yet, an amount of abrasive wear sometimes increases.
The linear movement of piston 14 excites compressor section 6, and this excitation always causes micro-vibration at spring 8 during the rotation of compressor unit 7. At the operation start or stop, compressor section 6 largely wobbles due to inertia force, and then spring 8 also wobbles, so that spring 8 contacts holders 20, 22 intermittently, and they scrape against each other. At this time, holders 20, 22 absorb the scraping noise since they are made from synthetic resin. Those techniques about compressors are disclosed in Japanese Patent Application Non-Examined Publication No. H06-81766.
The foregoing structure, however, needs holders 20, 22 separately because they are made from synthetic resin, so that the number of components and the manufacturing cost increase.
Since compressor section 6 largely wobbles at the operation start and stop, discharging path 22 also largely wobbles, so that path 22 contacts pipe 23 intermittently, and they scrape against each other. The scraping noise is absorbed by pipe 23 because it is made of polymeric material. However, this material is expensive because of its heat resistance, refrigerant resistance, and oil resistance.
In the compressor, the valves (not shown) for sucking and discharging the refrigerant gas between compressing room 13 and container 1 operate following the drive of compressor section 6. Then the valve port contacts the valve seat, thereby producing noises.
As such, the drive of compressor section 6 entails various sections to contact with each other or scrape against each other, so that the abrasive wear lowers the performance or produces noises. For overcoming the foregoing problems, the prior art requires additional components or expensive materials.